James Hansen's climate reckoning

The case for human-caused climate change

Storms Of My Grandchildren

by James Hansen

(Bloomsbury US,

2009;

$31.00)

In 2009, just before the Copenhagen conference, some scientists working on climate change models at the University of East Anglia were exposed for proposing that some data should be concealed. The chair of the Intergovernmental Panel on Climate Change was then widely criticized for predicting the precise year that Himalayan glaciers will disappear without any peer-reviewed evidence.

Reading James Hansen's Storms Of My Grandchildren makes it clear that these ballyhooed scandals in no way undermine the science of human-caused climate change. Hansen is a professor of Earth and Environmental Studies and was a director of NASA's Goddard Institute for Space Studies. He has been attempting to convince governments of the threat posed by carbon dioxide emissions since the 1980s. In this, his first book, he does not rely on computer models or on the integrity of particular scientists.

Hansen's conclusions are based on the demonstrable capacity of carbon dioxide to trap heat and on paleoclimatology. The more carbon dioxide in the atmosphere the less heat radiates back into distant space. Paleoclimatology -- the study of ancient ice cores and sediments -- confirms that rising levels of atmospheric carbon dioxide are consistently accompanied by rising global temperatures and rising sea levels.

Fifty million years ago when the landmass that is now India collided with Asia, extreme tectonic plate movements, earthquakes and undersea volcanoes brought massive amounts of methane hydrate to the surface where it burned, increasing atmospheric carbon dioxide levels to more than 1,000 parts per million (ppm). Average temperatures rose 12 degrees Celsius; sea levels rose 75 meters; many existing life forms disappeared.

Nature in more millennia has been kinder to our species. For the last 10,000 years -- until 50 years ago -- carbon dioxide in the atmosphere has remained between 200 and 300 ppm. Global climate and sea level have remained fairly constant, making agricultural development and expanding urban settlements in fertile coastal areas practical.

In 1960 carbon dioxide levels rose above 300 ppm. These have since risen by an annual average of two ppm, reaching 350 by 1980 and 390 by 2009. Some of the increasing atmospheric carbon dioxide is explained by rapid deforestation, most by the accumulating increase in the burning of fossil fuels.

The claim that rising carbon dioxide levels is not a problem, that rising global temperature is a result of increasing radiation from the sun, ignores science. Hansen points out that the sun over millions of years is getting hotter, but the effect in human time is not measurable. Radiation from the sun also rises and falls in cycles of ten or so years. Despite that, global mean annual temperatures have measurably and steadily risen since 1970.

Storms Of My Grandchildren makes the case that carbon in the atmosphere will within decades rise to 450 ppm unless fossil fuel usage is cut back substantially. At that level global mean temperatures will rise by two or three degrees. Permanent ice cover at the poles and higher altitudes will disappear. Floods, droughts and severe storms will become more frequent. The ocean, absorbing more carbon dioxide, will become more acidic; microscopic crustaceans, the beginning of the food chain for most sea life, will not survive.

The author calls for a reduction of atmospheric carbon dioxide to no more than 375 ppm. If instead all currently known petroleum reserves are exploited in this century, levels of atmospheric carbon dioxide would double. Temperatures could rise by five, 10 or more degrees Celsius. Sea levels could rise as much as 250 feet. As a first step in heading off catastrophe, Hansen proposes that all new coal, tar sands and shale gas development be immediately prohibited.

Hansen does not look beyond market solutions, but he does advocate free and open discussions. No partisan of a global warming establishment, he dismisses current environmental policies, pointing out that after the Kyoto Accord, carbon emissions in nearly all countries continued to steadily increase. He argues that "cap and trade" policies in effect allow enterprises and countries to increase their carbon emissions so long as they purchase indulgences. As an alternative, he proposes a carbon fee and dividend: a fee at source of $100 per ton of carbon emissions; the funds collected to be distributed equitably as dividends to everyone. Since people who pollute the most would pay the most, Hansen asserts that this would motivate people to look for alternatives to fossil fuel energy.

A scientist focused on his specialties, Hansen does not pretend to be a political expert. Much of Storms Of My Grandchildren describes his failure to convince U.S. governments of the dangers of continuing carbon emissions. The Bush-Cheney Administration responded to his concerns by prohibiting NASA employees from commenting on policy matters without prior White House approval. Hansen successfully appealed to Congress, pointing out that NASA's first priority, according to its mission statement was "to understand and protect our home planet." The White House then deleted these words from the mission statement and cut NASA's Earth Science budget by 20 per cent.

It is not surprising that capitalists and their supporters deny or minimize evidence of human-made climate change. Capitalism, a system driven to maximize profits, structurally resists policies that would limit growth in resource exploitation and money income.

The rest of us should be concerned with the future.

Before we jump on the bandwagon of climate change denial, we should ask, is it shocking that some scientists who warn of the dangers of global warming are arrogant, narrowly partisan and prepared to fudge the facts? Who expects better from the scientists, executives and lobbyists employed by petroleum, coal, finance, automobile, commercial transportation, agribusiness and media corporations with an interest in denying the problem?

More to the point where is the science that refutes Hansen's case? Where is the evidence that carbon dioxide is not a greenhouse gas? Where is the evidence that atmospheric carbon dioxide levels will not rise if fossil fuels continued to be burned at current, let alone higher rates? Where is the evidence that this will not lead to rising global mean temperatures, rising sea levels, worsening storms and the acidification of oceans?--Allan Engler